Proceedings of the Polytechnic Association: 097 



sing them to a red heat. The acid vapors thus generated pass 

 through several retorts filled with pumice stone and kept at a white 

 heat. Sulphuric acid is decomposed into sulphurous acid and oxygen. 

 The mixture is convej-ed through water, which leaves the oxygen 

 comparatively pure. 



CoMPosmox OF Meteokites. 



Messrs. Wiihler and Cloez have proved b}' analysis that certain 

 meteorites contain carbon, hydrogen and oxygen, forming substances 

 similar to some organic bodies of terrestrial origin. From the 

 meteorite Orgueil, M. Berthelot has obtained a notable quantity of 

 hydrocarbons similar to those found in petroleum. 



XlTEOUS OXYD FOR NeUEALGIA. 



Dr. G. Q. Colton, who has successfully administered laughing gas 

 to about S-ijOOO persons, for the purpose of performing dental opera- 

 tions without pain, and who, by persistent personal efforts in Europe, 

 has at last succeeded in introducing the use of this gas for similar pur- 

 poses in Paris and London, asserts that he has repeatedly cured the 

 most severe cases of neuralgia by allowing the patient to inhale the 

 gas. In many instances persons afflicted with asthma have been 

 greatly relieved. If these two terrible maladies can be cured, or 

 even partially controlled by laughing gas, we hope the medical 

 faculty will recommend its use with as little delay as possible. 



Blasting Geanite. 

 A mass of sound stone fifty feet square and twelve feet in thick- 

 ness, was recently moved some inches from its natural bed in the 

 granite quarries near Penryn, England, by the explosion of fifty 

 pounds of blasting powder, confined in a hole twelve feet deep by six 

 and one-half inches bored in the rock. Estimating the weight of 

 fifteen cubic feet of granite at one ton, the whole mass, containing 

 19,200 cubic feet, weighs 1,280 tons. 



Terra-Cotta Cisteens. 

 It is said that cisterns made of glazed terra-cotta are rapidly com- 

 ing into use in England. They are as valuable as those made of 

 elate, and are much cheaper. 



